U.S. patent number 4,596,862 [Application Number 06/685,528] was granted by the patent office on 1986-06-24 for olefin polymerization using chromium on fluorided aluminophosphate.
This patent grant is currently assigned to Phillips Petroleum Company. Invention is credited to Fay W. Bailey, Elizabeth A. Boggs, Max P. McDaniel, Donald D. Norwood, Emory W. Pitzer.
United States Patent |
4,596,862 |
McDaniel , et al. |
June 24, 1986 |
Olefin polymerization using chromium on fluorided
aluminophosphate
Abstract
Ethylene polymer is particularly suitable for the production of
tough film is produced under slurry conditions using a fluorided
aluminophosphate support and a reaction temperature within the
range of 93.degree. to 107.degree. C. in the presence of hydrogen
and a small amount of trialkyl boron cocatalyst wherein said
aluminophosphate has a phosphorous to aluminum ratio within the
very narrow range of 0.15 to 0.4 and wherein said aluminophosphate
carrying chromium catalyst is being activated at a temperature
within the range of 482.degree. to 704.degree. C. The resulting
film is not only substantially superior to film made from the best
of the readily available commercial resins but is also better than
film made from polymers using a similar catalyst system without the
specific combination of parameters of this invention.
Inventors: |
McDaniel; Max P. (Bartlesville,
OK), Pitzer; Emory W. (Bartlesville, OK), Boggs;
Elizabeth A. (Bartlesville, OK), Norwood; Donald D.
(Bartlesville, OK), Bailey; Fay W. (Bartlesville, OK) |
Assignee: |
Phillips Petroleum Company
(Bartlesville, OK)
|
Family
ID: |
24752590 |
Appl.
No.: |
06/685,528 |
Filed: |
December 24, 1984 |
Current U.S.
Class: |
526/106; 502/150;
502/210; 526/348.5; 526/352 |
Current CPC
Class: |
C08F
10/00 (20130101); C08F 10/00 (20130101); C08F
4/69 (20130101); C08F 210/16 (20130101); C08F
210/16 (20130101); C08F 210/14 (20130101); C08F
2500/12 (20130101); C08F 2500/07 (20130101) |
Current International
Class: |
C08F
10/00 (20060101); C08F 210/00 (20060101); C08F
210/16 (20060101); C08F 004/22 (); C08F
010/02 () |
Field of
Search: |
;526/106,156 |
References Cited
[Referenced By]
U.S. Patent Documents
|
|
|
2951816 |
September 1960 |
Hogan et al. |
4011382 |
March 1977 |
Levine et al. |
4077904 |
March 1978 |
Noshay et al. |
4347162 |
August 1982 |
Invernizzi et al. |
4364842 |
December 1982 |
McDaniel et al. |
4364855 |
December 1982 |
McDaniel et al. |
4481301 |
November 1984 |
Nowlin et al. |
|
Foreign Patent Documents
Primary Examiner: Smith; Edward J.
Attorney, Agent or Firm: Robbins; Archie L.
Claims
We claim:
1. A polymerization process comprising contacting a predominantly
ethylene monomer system under slurry polymerization conditions in a
hydrocarbon diluent with a catalyst comprising a chromium compound
on a fluorided aluminophosphate support produced by combining an
aluminum salt with a source of phosphate ions in a concentrated
mass and thereafter neutralizing to give a gel, said gel being
mixed with an acidic polar organic liquid containing a fluoriding
agent and worked until a reduction in volume occurs, said
polymerization being carried out utilizing a reaction temperature
within the range of 93.degree. to 107.degree. C. in the presence of
hydrogen in an amount within the range of 0.1 to 1.5 mole percent
based on diluent, a trialkylborane compound wherein the alkyl
groups have 1 to 5 carbon atoms per group, in an amount to give a
ratio of boron atoms to chromium atoms within the range of 0.04:1
to 1.5:1, said aluminophosphate having a phosphorus to aluminum
atom ratio within the range of 0.15 to 0.4, said aluminophosphate
carrying said chromium compound having been activated in air at a
temperature within the range of about 482.degree. to 704.degree.
C.
2. A method according to claim 1 wherein said polar organic liquid
is an alcohol and wherein said gel at the time it is worked is in
the form of a xerogel.
3. A method according to claim 2 wherein said fluoriding agent is
NH.sub.4 FHF.
4. A method according to claim 3 wherein said alcohol is
methanol.
5. A method according to claim 4 wherein said aluminum salt is
molten aluminum nitrate and said source of phosphate ions is
NH.sub.4 H.sub.2 PO.sub.4, said neutralizing being carried out
using concentrated ammonium hydroxide.
Description
BACKGROUND OF THE INVENTION
This invention relates to the polymerization of olefin monomers
using a chromium catalyst on an aluminophosphate support.
It is broadly known that the use of aluminophosphate supports for
chromium olefin polymerization catalysts gives a superior polymer.
However, for certain applications such as film it would be
desirable to tailor the resin to further enhance the tear strength
and impact strength of the resulting film.
SUMMARY OF THE INVENTION
It is an object of this invention to provide an olefin polymer
particularly suitable for film production;
it is a further object of the invention to provide an improved
olefin polymerization process; and
it is still a further object of this invention to provide film
having superior physical properties.
According to this invention an olefin monomer is polymerized at a
temperature within the range of 200-225 F. in the presence of 0.1
to 1.5 ppm of a trialkylborane cocatalyst using a chromium catalyst
on a fluorided aluminophosphate support activated at a temperature
within the range of 900-1300 F., said support having a P/Al atom
ratio within the range of 0.15 to 0.4.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The aluminophosphate support is made by a method disclosed in
McDaniel et al U.S. Pat. No. 4,364,855 the disclosure of which is
hereby incorporated by reference. In this method an aluminum salt
which will melt is used, with the source of phosphate ions combined
with the melt and then neutralized to give the hydrogel. Generally
those aluminum salts with a sufficiently low melting point are
hydrated. Orthophosphoric acid, orthophosphates such as
monoammonium phosphate and diammonium hydrogen phosphate or
mixtures of monoammonium and diammonium phosphate are preferred
sources of phosphate ions. As disclosed in this patent, some water
can be present and thus the method can broadly be viewed as
employing a concentrated mass of the acid phase (source of aluminum
and source of phosphate ions).
In the preparations involving an aqueous component in the
preparation of the aluminophosphate, it is preferred to remove
water from the hydrogel by azeotropic distillation or washing with
a volatile, water-miscible, low surface tension organic liquid. In
preparation techniques not employing water, any small amount of
water carried over from the water of hydration or from the base
used in the neutralization can be removed by conventional spray
drying, tray drying or oven drying thus avoiding the necessity for
azeotropic distillation. However, even in these situations, if it
is desired to water wash the hydrogel then azeotropic distillation
or washing with a solvent is desirable. After drying of water in
this manner, the gel is preferably dried of solvent under mild
conditions, for instance by heating at a temperature of 25.degree.
to 110.degree. C., most preferably under vacuum.
It may be desirable in some instances to coprecipitate other
materials with the phosphate or have other materials present during
the gelation. For instance, the chromium compound such as chromium
nitrate can be introduced with the reactants.
The neutralization can be carried out by either adding the acid
phase to the base phase (neutralizing agent) or vice versa, or by
adding both to a third vessel. One suitable practice is to drip the
acid phase into the base phase or otherwise add the acid phase
relatively slowly into the base phase with stirring. This results
in the production of small spheres or balls of the orthophosphate,
particularly where the melt of aluminum salt and source of
phosphate ions is dripped or sprayed or otherwise slowly added to a
large excess of ammonium hydroxide. The spheres are subsequently
collected, washed, dried and calcined.
Gelation occurs spontaneously at a pH of about 4, which is achieved
by combining about 72 percent of the neutralizing agent, and it has
been found that this is not desirable. Therefore, the
neutralization is preferably achieved by either: (1) combining
slowly with stirring the acid phase and about 72 percent of the
amount of neutralizing agent (base phase) needed for complete
neutralization and thereafter quickly adding the rest of the
neutralizing agent so as to achieve gelation at a pH of 5 or
greater, preferably at least 6, generally 6 to 10, or (2) combining
all of the base phase with the acid phase under rapid conditions so
as to achieve gelation at a pH of 5 or greater, preferably at least
6, generally 6 to 10.
While any base can be used as the neutralizing agent, concentrated
ammonium hydroxide, ammonia gas, or ammonia dissolved in an alcohol
or other nonaqueous solvent is preferred. Other suitable
neutralizing agents include ammonium carbonate used alone or in
combination with ethylene oxide and propylene oxide.
The atom ratio of phosphorus/aluminum must be within the relatively
narrow range of from 0.15 to 0.4 preferably 0.2 to 0.3, most
preferably about 0.2, thus in all instances giving an amorphous
aluminum orthophosphate composition.
While low phosphorous aluminum phosphate can be thought of for
convenience as a mixture of aluminum phosphate and alumina, it in
fact is not. No alumina is present at all but rather there is a
unitary amorphous gel matrix structure in which some of the
trivalent PO.sub.4 groups of the aluminum phosphate are replaced
with trivalent AlO.sub.3 groups. Herein such materials are referred
to as aluminophosphates.
The chromium compound can be coprecipitated as noted hereinabove or
can be added to the hydrogel or xerogel. The term xerogel is used
to refer to predominantly amorphous gel resulting from the removal
of free water from the hydrogel. For instance, a water-soluble
chromium compound such as chromium nitrate, chromium acetate, or
CrO.sub.3 can be added to the hydrogel. Alternatively, a chromium
compound soluble in an anhydrous solvent such as a hydrocarbon can
be used to impregnate the xerogel prior to activation. Suitable
chromium for such anhydrous impregnation includes tertiary-butyl
chromate. The chromium compounds are used in amounts sufficient to
give 0.1 to 5 preferably about 1 weight percent chromium based on
the weight of the xerogel base plus chromium compound. Preferably
the chromium compound is added by means of an aqueous solution of a
chromium compound such as chromium nitrate which is added to the
hydrogel.
The phosphate support is activated at a temperature within the
range of 482.degree. to 704.degree. C. (900.degree.-1300.degree.
F.), with 593.degree. to 649.degree. C. (1100.degree.-1200.degree.
F.) being preferred. The activating ambient is air or other similar
oxygen-containing ambient. The chromium compound is at least
predominantly in the hexavalent state after activation. Activation
times of 5 minutes to 24 hours, preferably 1/2 to 10 hours are
suitable for the activation or calcining step. The chromium is
thought to be reduced in the polymerization zone by the monomer,
probably to a plus 2 oxidation state. If desired this reduction can
be carried out before the catalyst is contacted with the monomer,
for instance in the activation step.
The aluminophosphate must be given a fluoriding treatment. This is
preferably done by mixing the xerogel with a solution of a fluoride
such as ammonium bifluoride (NH.sub.4 FHF), ammonium fluoroborate
(NH.sub.4 BF.sub.4), ammonium silicofluoride [(NH.sub.4).sub.2
SiF.sub.6 ] or aluminum fluoride (AlF.sub.3). An alcoholic solution
of the NH.sub.4 FHF is particularly suitable. Also aqueous
solutions of these compounds can be used. Alternatively the
fluoriding component can be added to the hydrogel or the xerogel
after calcining. Also the fluoriding agent can be added to the
activator. Suitable fluoriding agents for this include those listed
above plus gases such as PF.sub.3 or PF.sub.5 (phosphorous
trifluoride and phosphorous pentafluoride). The preceding are
preferred because they contain as the other ion either NH.sub.4
which can be driven off, or P or Al which are not harmful to the
final catalyst.
The boron cocatalyst is a trialkylborane, the alkyl group having
from 1 to 5 carbon atoms per group. Triethylborane (TEB),
tripropylborane, and tri-n-butylborane are preferred. The boron
compound is used in an amount so as to give an atom ratio of boron
to chromium within the range of 0.04:1 to 1.5:1, preferably 0.09:1
to 1.1:1, more preferably 0.09:1 to 0.50:1. Stated in parts by
weight per million parts by weight of the diluent, the amount of
boron cocatalyst is within the range of 0.1 to 15 ppm, preferably
0.25 to 1.0, more preferably 0.25 to 0.5 ppm.
The boron-containing cocatalyst can be either premixed with the
catalyst or added as a separate stream to the polymerization zone,
the latter being preferred.
Hydrogen is used in an amount within the range of 0.1 to 1.6 mole
percent based on the moles of diluent. Preferably the amounts are
within the range of 0.4 to 0.8 mole percent based on diluent. By
mole percent is meant the mole percent hydrogen based on the total
moles of hydrogen, diluent and ethylene in the off-gas, but this is
essentially the same as mole percent based on the moles in the
reactor.
By utilizing low levels of TEB based on chromium, hydrogen can be
maintained in the cited range to control polymer melt flow, or
maintaining hydrogen in the cited range permits the use of low TEB
levels which is desirable to control the amounts of low MW polymer.
It is this interaction of critical amounts of cocatalyst, hydrogen,
reactor temperature and catalyst activation temperature in
combination with the fluoriding at the aluminophosphate support
which applicants have found surprisingly gives greatly enhanced
film properties.
The catalyst of this invention comprising a chromium compound on an
aluminophosphate base is used with a trialkylborane cocatalyst to
polymerize a monomer system generally consisting essentially of
ethylene in a slurry polymerization system using conventional
equipment and contacting processes. While the monomer feed is
generally essentially ethylene, the polymer produced may have
slightly lower density than the 0.960 normally associated with
ethylene homopolymer. If desired, a small amount of one or more
comonomers selected from mono-1-olefin having 3-8 carbon atoms per
molecule can be included in the feed. Preferred are 1-butene,
1-pentene, 1-hexene and 1-octene. If used, the comonomer would be
used in an amount within the range of 0.1 to 5 weight percent
comonomer in the feed to give a polymer having 98 to 99.9 weight
percent ethylene incorporation.
Contacting of the monomer with the catalyst can be effected in any
manner known in the art of slurry polymerization. Briefly, this
involves suspending the catalyst in an organic medium and agitating
the mixture to maintain the catalyst in suspension throughout the
polymerization process. The diluent is a normally liquid
hydrocarbon such as n-pentane, n-hexane, cyclohexane, n-butane or
isobutane. During this polymerization the reactor temperature
(temperature of the reactor contents during polymerization) is
within the range of 200.degree.-225.degree. F.
(93.degree.-107.degree. C.), preferably 210.degree.-220.degree. F.
(99.degree.-104.degree. C.), most preferably
210.degree.-215.degree. F. (99.degree.-102.degree. C.). The higher
temperatures give polymers having better toughness properties such
as tear strength resistance but cause reductions in catalyst
productivity.
In an optional more specific embodiment of this invention, the
aluminophosphate is mixed with a polar organic liquid acidic
composition and worked until a reduction in volume occurs. More
specifically this treatment comprises: (1) combining an acid
composition in a liquid polar organic compound with the particulate
refractory material to give a workable mixture; (2) working the
mixture, for instance by stirring, during which time a decrease in
volume occurs; (3) shaping the material into beads, pellets,
extrudate, bricks or other shapes; (4) drying the shaped mixture;
and (5) subjecting the dried product to conventional treatment such
as grinding and calcining.
The polar organic compound can be an ester, ketone, aldehyde,
alcohol or other normally liquid polar organic compound or mixture
thereof. Alcohols are preferred, particularly 1-6 carbon atom
alkanols, most preferably methanol because of its hydrophilic
nature.
The acid can be either a mineral acid such as nitric acid or
hydrochloric acid or sulfuric acid or it can be an organic acid,
such as acetic acid, oxalic acid or propionic acid, for instance.
Alternatively, instead of an acid as such, a compound imparting
acidic characteristics to the composition can be used to produce
the acid composition. For instance, chromium nitrate can be used to
provide both the chromium for the catalyst and the acidic
conditions. Generally, the acidic salt will give a pH of 2 to 4
when dissolved in water to form a 0.1M solution. Examples are
chromium(III) nitrate, chromium(VI) oxide, aluminum nitrate,
NH.sub.4 H.sub.2 PO.sub.4, aluminum sulfate and chromium sulfate. A
particularly preferred acidic material is a fluoride such as
ammonium bifluoride which not only aids in agglomeration but also
gives the surface fluoride treatment.
The amount of acid used is preferably sufficient to give about 0.02
to about 0.5 normality/liter in a polar organic compound.
The working to reduce the volume can be done with any mixing device
capable of mixing the composition. The polar organic liquid is
preferably used in an amount sufficient to give initial incipient
wetness. This is about one volume of liquid per total volume of
voids and pore volume of the refractory material. Broadly, liquid
in an amount from about 0.1 to 2 times the total volume represented
by the voids and the pore volume can be used. Stated another way,
the polar organic liquid is preferably used in an amount within the
range of 0.3 to 5 preferably 1-3 milliliters per gram of solid
particulate aluminophosphate or 1-25 preferably 2-7 milliliters per
gram of aluminophosphate on a dry basis when the treatment is done
in the gel stage. As the mixing continues, the volume of solids
decreases and free liquid is released. The mixing can continue with
the mixture getting less viscous because of the free liquid, but
preferably, the thus-released liquid is evaporated to keep the
consistency the same or more preferably to cause the mass to become
more viscous. Eventually, the mass will become, to all outward
appearances, a solid, although generally the mixing is stopped
short of this point. The reason for this is that in accordance with
the invention, voids are reduced and particles are thus
agglomerated without significant damage to the pores of the
refractory material. Carrying the mixing to the point where the
material totally solidifies can result in damage to the pores or in
particles which are too strong for being fragmented during
polymerization. Stated in terms of mixing time, the mixing time can
vary, of course, depending on the intensity, with more intensive
mixing requiring less time. Generally 10 minutes to 15 hours,
preferably 1 to 3 hours is used.
The terms mixing and working are used herein to describe the
procedure employed on the aluminophosphate. In the examples a
planetary mixer was used. A granulater has also been used. The
procedure is most nearly analogous to kneading bread dough. Hence,
machines such as pin granulaters, sigma mixers or banbury-type
mixers designed to give intensive working can be utilized. The
aluminophosphate can be either new aluminophosphate or the fines
resulting from processing of a refractory material, that is the
invention can be applied to a refractory material as produced, or a
refractory material (with or without having been agglomerated in
accordance with the invention) can have fines separated therefrom
and the fines only subjected to the acid treatment.
In a second aspect of this specific embodiment, a hydrogel or a gel
wherein the water in the pores has been partially or essentially
completely replaced with a water miscible volatile liquid organic
compound such as an alcohol, preferably a 1-6 carbon atom alcohol,
is subjected to the same treatment described hereinabove with
respect to the particulate solid material. As with the first
aspect, the preferred polar organic compound is methanol.
Although on initial working the gel will have a different
consistency than the particulate aluminophosphate, on milling or
working of the gel it is reduced in volume due to evaporation of
the polar liquid and approaches apparent dryness. Hence the same
types of mixing equipment can be used as with the first aspect. In
the second aspect the polar organic compound can simply be the
material used for removing water from the hydrogel, these materials
being water miscible normally liquid volatile polar organic
compounds such as alcohols with methanol, as noted hereinabove
being preferred. Initially the pores are filled with water i.e. the
material is a hydrogel. Milling or mixing can be initiated at this
point or after some or essentially all of the water has been
displaced with the polar organic compound. The acidic material is
combined with the polar organic compound in the same manner as in
the first aspect, preferably using an acidic chromium compound so
as to impart chromium to the refractory material. After the
treatment is complete the resulting milled or mixed material is
dried of remaining liquid and calcined in the same manner as in the
first aspect. Generally, the milled material is introduced into a
hammermill or other device utilizing high speed blades or chains to
pulverize the material.
There is one difference between the first and second aspects in
that, because the solids content of the gel in the second
embodiment is relatively low i.e. 10 to 25 percent generally, a
greater amount of polar organic compound is used based on the
weight of the refractory material on a dry basis. Generally 1 to 20
preferably 2 to 7 milliliters of polar organic liquid per gram of
aluminophosphate based on a solid basis is used, as noted
above.
EXAMPLES
The various physical properties of the polymers produced according
to the instant invention were measured according to the following
procedures.
HLMI, g/10 min; ASTM D 1238-65T, condition F
MI, g/10 min; ASTM D 1238-65T, condition E
Density, g/cc; ASTM D 1505-68
Bell ESCR, F.sub.50, hrs; ASTM D 1693-70, condition A (50.degree.
C.)
Dart impact, g; ASTM D 1709-75. Energy needed to rupture one mil
thick film upon impact of a free falling dart. This method
establishes the weight of the dart dropped from a height of 26
inches which causes 50 percent of the samples to break. The
staircase method is used to determine the 50 percent failure level
and the missile weight increment is 15 g. In all instances the film
was 1 mil in thickness.
Elmendorf tear, t/mil; ASTM D 1922. This is a modification for
polymer film adapted from the Elmendorf tear test used for paper.
This method determines the average energy in grams required to
propagate a tear through 2.5 inches of film in the machine
direction (MD) or transverse direction (TD) as indicated. In all
instances the film was 1 mil in thickness.
Spencer impact, joules; ASTM D 3420. This test measures the energy
needed to burst and penetrate the center of a one mil thick film
specimen mounted between two rings with a 31/2 inch (1.38 cm)
diameter. The following formula is used to obtain impact values in
joules.
E=RC/100; E=Energy to rupture, joules; C=apparatus capacity, 1.35
joules; R=scale reading on a 0 to 100 scale.
Fisheyes, count/ft.sup.2. The number of fisheyes per square foot of
one mil thick film determined visually.
Catalyst productivity is given in terms of g polymer per g solid
catalyst per unit average residence time in the loop reactor under
steady state conditions, generally about 11/4 hours.
In the following invention runs the aluminum phosphate support was
prepared by the melt method as disclosed in U.S. Pat. No. 4,364,855
(Dec. 21, 1982), the disclosure of which is hereby incorporated by
reference. Specifically, Al(NO.sub.3).sub.3.9H.sub.2 O was heated
to about 80 C. to form a melt. The quantity of NH.sub.4 H.sub.2
PO.sub.4 necessary to give the desired atom ratio of P/Al was
dissolved in the melt, and chromium nitrate was added to give the
indicated amount of chromium. Sufficient concentrated NH.sub.4 OH
was mixed with the melt to neutralize and form a gel. The resulting
gel was washed with alcohol and dried.
The aluminophosphate was prepared by contacting an aqueous solution
containing sufficient Al(NO.sub.3).sub.3 and NH.sub.4 H.sub.2
PO.sub.4 to produce an atom ratio of P/Al 0.2 to 0.3 as
specifically set out in the example. Ammonium hydroxide is added to
produce a gel at a pH of about 6. The gel was washed with hot
(80.degree. C.) water to remove soluble byproducts and then with
isopropanol to reduce the water content. The treated gel was dried
at 80.degree. C. in a vacuum oven and the dry product calcined in
air at the indicated temperature to produce the final product.
EXAMPLE I
In this example the phosphorous to aluminum ratio was 0.2 and
chromium level was 1 weight percent chromium introduced in the form
of chromium nitrate to the hydrogel. The activation temperature was
1200 F. In invention Run 2 the dried xerogel was contacted with 3%
ammonium bifluoride in methanol and worked prior to activation. The
ethylene polymerization was carried out at 210 F. with 0.5 ppm TEB
in isobutane with hydrogen as a molecular weight control agent in
the amount of 1.49 mole percent based on diluent. Results are set
out hereinbelow in Table I.
TABLE I ______________________________________ Elmen- Pellet
Produc- Dart dorf Fluo- Den- tivity Drop Tear Run rided HLMI sity
g/g/hr (g) TD,(g) ______________________________________ 1 (Con- No
13.2 0.9599 2560 212 272 trol) 2 (Inven- Yes 11.9 0.9551 2270 234
421 tion) ______________________________________
The data in Table I shows a dramatic improvement in film properties
as evidenced by modest improvement in dart drop and a major
improvmeent in Elmendorf tear. In this regard it is significant
that the control run represents a newly developed product far
superior to the resins that have been on the market in the past.
The best commercial products would have tear strengths in the
machine direction generally of less than 200 or at most 250.
Similarly the dart drop impact for the best of commercial resins
under similar conditions would generally be less than 200.
EXAMPLE II
The invention runs of Example II were carried out under identical
conditions (P/Al=0.2, 1.0% Cr) as those of Example I except 1
percent ammonium bifluoride solution is utilized and the activation
was carried out for 5 hours at 1200.degree. F. Results are set
forth below in Table II in comparison with two of the best
commercial resins readily available on the market.
TABLE II
__________________________________________________________________________
9 10 Hostalen Arco 9225F2 6000 3 4 5 6 7 8 Commercial Commercial
Invention Invention Invention Invention Invention Invention Control
Control
__________________________________________________________________________
TEB, ppm 0.56 0.53 0.52 0.50 1.04 1.08 -- -- H.sub.2 mole % 1.01
0.91 0.68 0.62 0.79 0.63 -- -- Productivity g/g 2,110 2,170 2,330
2,330 2,290 2,300 -- -- Time, Min. 75 75 75 75 75 75 -- -- Melt
Index, g/10 min 0.15 0.11 0.07 0.06 0.11 0.08 0.08 0.06 HLMI, g/10
min 17.4 14.2 10.1 9.0 14.2 11.5 9.6 9.3 Density, g/cc 0.9553
0.9549 0.9547 0.9548 0.9555 0.9533 0.9489 0.9526 Flexural Modulus,
MPa 1,230 1,230 1,200 1,240 1,240 1,240 1,200 1,340 Flexural
Modulus, psi 178,000 178,000 174,000 180,000 180,000 179,000
174,000 194,000 Melt Temperature, .degree.C. 225 226 245 250 225
225 247 237 Dart Impact, g 212 239 244 274 227 265 170 196 Spencer,
Joule 0.45 0.58 0.56 0.62 0.45 0.49 0.40 0.38 Tear, MD, g 32 36 30
34 30 34 25 23 Tear, TD, g 362 397 285 312 368 323 165 156
Fisheye/ft.sup.2 gel 8.0 9.0 7.0 7.0 8.5 7.0 5.0 15
__________________________________________________________________________
EXAMPLE III
In this example the polymer was made as in Example I except 4
percent solution of ammonium bifluoride was used. Results are set
out herein below in Table III in comparison with an example of one
of the best of readily available commercial materials.
TABLE III ______________________________________ 13 Holstalen
9255F2 11 12 Conventional Run Invention Invention Control
______________________________________ TEB, ppm 0.55 0.94 --
H.sub.2, Mole % 1.29 0.67 -- Hexene-1, Wt. % 0.29 1.73 --
Productivity g/g 1,610 1,210 -- Time, Min. 75 75 Melt Index, g/10
min 0.09 0.05 0.08 HLMI, g/10 min 13.7 9.7 9.6 Density, g/cc 0.9551
0.9502 0.9489 Flexural Modulus, MPa 1,210 1,070 1,200 Flexural
Modulus, Psi 175,000 155,000 174,000 Dart Impact, g 226 232 145
Spencer, Joule 0.43 0.55 0.40 Tear, MD, g 26 37 23 Tear, TD, g 480
464 187 Fisheye/ft.sup.2 gel 20.0 16.0 5.5
______________________________________
EXAMPLE IV
This example demonstrates properties of films made from polymer
produced from catalyst identical to that of Example III except the
fluoriding was done with a 2 weight percent solution of the
ammonium bifluroide. Results are set out herein below in Table
IV.
TABLE IV
__________________________________________________________________________
14 15 16 17 18 19 Run Invention Invention Invention Invention
Invention Invention
__________________________________________________________________________
TEB, ppm 0.53 0.59 0.48 0.54 0.53 0.48 H.sub.2 mole % 1.25 1.04
0.92 1.22 1.14 0.92 Hexene-1, wt. % 0 0 0 1.76 1.73 0 Productivity
g/g 2,080 2,220 2,410 1,260 1,450 2,410 Time, Min. 75 75 75 75 75
Melt Index, g/10 min 0.08 0.06 0.05 0.10 0.08 0.05 HLMI, g/10 min
12.1 10.7 7.8 14.9 13.2 7.8 Density, g/cc 0.9554 0.9549 0.9549
0.9488 0.9503 0.9549 Flexural Modulus, MPa 1,200 1,210 1,190 989
1,070 1,190 Flexural Modulus, psi 174,000 175,000 173,000 143,000
155,000 173,000 Melt Temperature, .degree.C. 226 230 245 230 230
267 Dart Impact, g 230 229 331 239 246 286 Spencer, Joule 0.47 0.57
0.56 0.55 0.57 0.52 Tear, MD, g 32 29 29 35 41 27 Tear, TD, g 326
389 238 547 512 246 Fisheye/ft.sup.2 gel 5.0 5.0 3.5 6.5 10.0 4.5
__________________________________________________________________________
Of particular interest is run 16 which shows a dart impact strength
of 331 grams which is roughly double of what would be expected from
the best of the readily available commercial resins under similar
conditions.
Further with regard to the data and examples I to IV, it is
essential for the comparisons to be made at the same HLMI since it
is desirable to have higher HLMI in order to improve
processability, but this detracts from the toughness of the film.
As can be seen in the comparisons with the commercial control, the
polymers of the invention exhibit enhanced properties at the same
or even at higher HLMI values. Thus it is possible in accordance
with the invention to have both better processability and greater
toughness. Many more runs have been made than are reported herein,
these runs being representative. In some runs where the invention
catalyst is compared with identical catalyst except without the
fluoriding, wherein fluorided catalyst is used to produce slightly
higher melt of flow, the results are about comparable. With all
factors being held constant the advantage for the fluoriding shown
in Example I is representative of the consistent beneficial effect
of the fluoriding.
While this invention is being described in detail for the purposes
of illustration it is not to be construed as limited thereby but it
is intended to cover all changes and modifications within the
spirit and scope thereof.
* * * * *